A telephone network typically comprises an array of switching offices which are interconnected by trunks. Typically, individual users are connected to particular local switching offices by way of subscriber loops. A typical telephone conversation between first and second users involves the subscriber loop connecting the first user to its local switching office, a plurality of trunks and other switching offices connecting the local switching office of the first user to the local switching office of the second user, and the subscriber loop connecting the second user to its local switching office. Illustratively, the switching offices may be No. 1 or No. 1A ESS switching offices or No. 5 crossbar switching offices.
In general, trunk lines in a telephone network are tested automatically, illustratively, by determining losses at various frequencies. The trunk lines to be tested are chosen under the control of a computerized system known as Centralized Automatic Reporting on Trunks (CAROT). In addition to choosing the trunks to be tested, the CAROT system receives and analyzes data representing test results from particular trunks.
The CAROT computer is typically located at a remote test location in the telephone network which is connected to a local switching office via a subscriber loop. The remote test location can set up a test of a trunk connecting a near end switching office and a far end switching office. The near end switching office is a type of switching office known as a ROTL (Remote Office Test Line) office. A ROTL switching office is a switching office which contains a ROTL frame circuit. The ROTL frame can selectively test any trunk leaving the ROTL office upon receipt of appropriate test priming information from the remote test location containing the CAROT computer. The ROTL frame includes a ROTL applique circuit which serves as an interface between various elements associated with the ROTL frame such as ports, responders, tone detectors, and test progress tone generators. Illustratively, the hardware connections of the ROTL applique circuit may be controlled by a ROTL program which is resident in the central processor of the ROTL switching office.
A test of a trunk connecting a near end or ROTL office and a far end office is set up as follows. A connection is first set up between the remote test location and the near end or ROTL office via the telephone network. Priming information concerning the test to be carried out is transmitted from the remote test location via the ROTL applique circuit to a receiver in the near end switching office. The test priming information includes information concerning the trunk to be tested and the identity of a far end test line which is a test line to be connected to the trunk to be tested by the far end switching office. The priming information is used to set up a connection between the near end office and the far end office via the trunk to be tested. More particularly, a connection is established by way of the trunk to be tested between a near end responder, which is connected to a near end test line associated with the near end switching office, and a far end responder which is connected to the far end test line. To set up the connection to the far end test line, the near end switching office, under the control of its central processor, transmits a directory number indicative of the far end test line to the far end switching office via the trunk to be tested. The far end switching office, under the control of its own central processor, then connects the trunk to be tested to the far end test line.
Once the desired connections are set up, the CAROT computer informs the near end responder and/or far end responder as to the type of test to be carried out. The tests are carried out by transmitting signals between the near and far end responders via the trunk under test. Once the tests are carried out the results are transmitted back to the CAROT computer.
Unfortunately, the above-described mechanism cannot be used to set up a test of a trunk leading to an ACD such as a No. 5 ACD. An ACD is used, for example, to route a request for directory assistance to an available operator position. A near end switching office such as a No. 1 ESS transmits a request for directory assistance by placing a short circuit across the relevant trunk line leading to the ACD. The request is then routed under the control of a marker or other central processing unit in the ACD to an available operator position. As normally configured, a near end switching office, such as a No. 1 or No. 1A ESS or a No. 5 crossbar, cannot cause a connection to a specific operator position associated with an ACD to be established by transmitting to the ACD a directory number indicative of the specific operator position. The ACD merely sets up connections to available operator positions in response to service requests communicated in the form of short circuits via a trunk leading to the ACD. Similarly, a ROTL switching office cannot normally cause a connection with a test line of ACD to be established by transmitting a number indicative of the test line to the ACD. Thus, a trunk leading to an ACD cannot normally be tested from the remote CAROT testing location.
Accordingly, trunks leading to an ACD are tested manually. Such manual testing is slow and expensive and as a result may not be performed as often as desired. Accordingly, service quality problems have plagued trunks leading to ACDs more frequently than other kinds of interoffice trunks.
In view of the above, it is an object of the present invention to provide a mechanism which enables trunks leading to ACDs to be tested automatically by the CAROT computer from a remote test location.